Macrihanish is maintained on a 'Care & Maintenance' basis and is available 'as required' to units. Also it's available for emergencies. I don't remember much there in the way of accommodation, although there are a hangars and a tower still (and a high fence)
In the past it's been used by U2 operations and there have also been rumours about it's use by the Aurora project (don't know if it's true).
I think that permanent re-activation is pretty unlikely
Arc